1. Field
Embodiments relate to a battery pack.
2. Description of the Related Art
A battery pack used in an electric vehicle or a hybrid electric vehicle (HEV) may include a plurality of battery cells that are electrically connected so as to supply a high amount of power. The plurality of battery cells included in the battery pack may be electrically connected in series, in parallel, or in a combination of serial and parallel connections. A connection status of the battery cells may be determined in consideration of a desired output voltage of the battery pack, a use time of the battery pack, or the like. For example, when a high output is demanded, the battery cells may be connected in series; and when a long period of use is demanded over a high output, the battery cells may be connected in parallel.
Typically, in a battery pack according to the related art, the connection status of the battery cells in the battery pack is fixed; and thus, the output of the battery pack is also fixed. Since the output of the battery pack is fixed, when a situation with respect to using the battery pack is changed, it may be difficult to deal with the change. That is, if a load connected to the battery pack is changed, it may be difficult to deal with the change.
An output of the battery pack may be changed by using a direct current-to-direct current (DC-DC) converter. However, it may be difficult to use the DC-DC converter in a system demanding a high current, e.g., in a battery pack for an electric vehicle, which generally supplies high current to a load.